// Noise-Setup: verschiedene Noise-Funktionen fuer Terrain, Biome und Hoehlen
import { createNoise2D, createNoise3D } from 'simplex-noise';
import { WORLD_SEED } from './constants.js';
import { mulberry32 } from './rng.js';

// Wir leiten mehrere unabhaengige Streams aus dem Seed ab, damit
// verschiedene Noise-Quellen (Hoehe, Temperatur, Hoehlen) nicht korrelieren.
const rngTerrain = mulberry32(WORLD_SEED);
const rngTemp = mulberry32(WORLD_SEED ^ 0x9e3779b9);
const rngHumid = mulberry32(WORLD_SEED ^ 0x85ebca6b);
const rngCave = mulberry32(WORLD_SEED ^ 0xc2b2ae35);
const rngDetail = mulberry32(WORLD_SEED ^ 0x27d4eb2f);

export const noise2DTerrain = createNoise2D(rngTerrain);
export const noise2DDetail = createNoise2D(rngDetail);
export const noise2DTemp = createNoise2D(rngTemp);
export const noise2DHumid = createNoise2D(rngHumid);
export const noise3DCave = createNoise3D(rngCave);

// Fraktale Brownian Motion (fbm) in 2D
export function fbm2(noiseFn, x, z, octaves, lacunarity, gain) {
  let amp = 1, freq = 1, sum = 0, norm = 0;
  for (let o = 0; o < octaves; o++) {
    sum += amp * noiseFn(x * freq, z * freq);
    norm += amp;
    amp *= gain;
    freq *= lacunarity;
  }
  return sum / norm; // [-1,1]
}